Blocking members of this kind and a vulcanization mold equipped therewith are known from DE 199 00 596 A1. In this arrangement each blocking member consists of a pin-like central body which can be fixed in force-transmitted manner into the respective vent bore and also of a sealing part connected to the central body which has a surface region disposed at the inner side of the mold with at least one aperture and which, together with the mold side end face of the central body, forms a flow path for the air with a pronounced angled shape following the aperture. This known embodiment has proved itself in practice.